When Alexa spoke to her grandparents after the audition she was "overwhelmed" at the judges' responses.
"She couldn't believe it," Mr Eggleton said. "It was all her dreams come true".
Alexa's mum, Michelle Curtis, grew up in Whangarei and attended Whangarei Primary School, Tikipunga Area School and Tikipunga High School.
Mrs Curtis, husband Tony and their eldest child Aidan, now 15 years old, lived in Auckland but moved to Australia before Alexa was born.
However, the family's connection to New Zealand is still strong with Christmas often happening at the Eggleton home in Russell.
Alexa's grandparents travelled back to Australia in July to watch her final performance.
"You could see that she had had some guidance on all levels," Mr Eggleton said.
Mr and Mrs Eggleton were back in New Zealand waiting by the phone when the show, and Alexa's win, aired in Australia.
They jumped up and down, cheered and even opened a bottle of champagne when they heard.
Since the win, Alexa recorded her single Playground.
Alexa had no musical training before the show, but Mr Eggleton, who pays in a rock/blues cover band, said he had a hand in her success.
"I like to think she got a little bit from me," he said.